The present disclosure relates to a method of producing a composite for acid gas separation having an acid gas separation function.
Recently, development of technologies for selectively separating acid gases in mixed gases has been in progress. In particular, development of technologies for selectively separating carbon dioxide have been making progress. Such developments include, for example, a technology for collecting and concentrating carbon dioxide in exhaust gases as a countermeasure against global warming, and a technology for obtaining a hydrogen-based gas for use in fuel cells and the like by steam reforming hydrocarbons to hydrogen and carbon monoxide (CO), then generating carbon dioxide and hydrogen by reacting the carbon monoxide and water vapor, and eliminating the carbon dioxide through a membrane that selectively permeates the carbon dioxide.
As an acid gas separation membrane that selectively permeates and separates an acid gas, a facilitated transport membrane is known in which an acid gas is separated by transporting the acid gas from the raw gas feed side of the membrane to the opposite side by an acid gas carrier contained in the membrane.
For example, Japanese Examined Patent Publication No. 7(1995)-102310 describes a manufacturing method of a composite for carbon dioxide separation in which uncross-linked vinyl alcohol-acrylate copolymer solution is coated in a film on a carbon dioxide permeable support to form a liquid film of the uncross-linked vinyl alcohol-acrylate copolymer solution on the support, then the liquid film is heated to cause cross-linking to produce a water insoluble film, and an aqueous solution containing carbon dioxide carrier (substance having affinity to carbon dioxide) is absorbed in the water insoluble film to produce a hydrogel film, thereby forming a facilitated transport membrane formed of the hydrogel film supported on the support as the composite for carbon dioxide separation.
Japanese Unexamined Patent Publication No. 2012-143711 describes a manufacturing method of a composite for carbon dioxide separation in which an coating liquid prepared by adding a gelling agent, such as agar, to an coating liquid containing a polyvinyl alcohol-polyacrylic acid copolymer and alkali metal carbonate and heating at a temperature greater than or equal to 50° C. is coated on a support, and the liquid film is cooled to be gelated and dried, thereby forming a facilitated transport membrane supported on the support as the composite for carbon dioxide separation.
Japanese Unexamined Patent Publication No. 2011-183379 describes a manufacturing method of a composite for acid gas separation having a gas separation membrane formed by coating a coating liquid to a layered film formed by layering a hydrophilic porous film and a hydrophobic porous film and permeating the coating liquid to a portion of the porous film.